Sr. Software Developer

System One, Inc.; Gaithersburg (MD); On-site; USD 140,000 - 180,000; Full time

Job summary

System One, Inc. is seeking a Senior Software Engineer in Gaithersburg, MD to design, develop, and maintain mission-critical enterprise applications in a hands-on Agile environment. The role requires active Top Secret/SCI clearance with polygraph readiness and extensive experience in Java, C#, Python, or C++.

You will collaborate with product owners, architects, and DevSecOps teams to build secure, scalable software, and to support CI/CD pipelines and automated deployments in an onsite setting.

Qualifications

• Active Top Secret/SCI clearance
• polygraph examination required
• 8–12 years of relevant software experience with a bachelor’s degree, or 6–10 years with a master’s degree
• 8+ years of professional software development experience
• Experience with at least one OOP language (Java/C#/Python/C++)
• Experience building web-based enterprise software and RESTful APIs
• Experience with relational/NoSQL databases and Agile/Scrum environments
• Strong debugging, analytical, and communication skills

Responsibilities

• Design, develop, test, deploy, and maintain enterprise software applications
• Write clean, secure, well-documented code following best practices
• Design and implement RESTful APIs and microservices
• Participate in Agile ceremonies and collaborate across teams
• Develop automated tests for unit, integration, and end-to-end scenarios
• Conduct code reviews and mentor junior developers
• Troubleshoot complex issues and perform root cause analysis
• Support CI/CD pipelines and automated deployments
• Optimize performance, scalability, and security
• Contribute to architecture discussions and technical roadmaps
• Support production deployments in mission-critical environments

Skills

Java

C#

Python

C++

Education

Bachelor’s degree in Computer Science or related field

Master’s degree in Computer Science or related field

Tools

Git

Docker

Kubernetes

Terraform

Job description

Senior Software Engineer

Location: Gaithersburg, MD
Schedule: Full Time
Work Arrangement: Onsite
Travel Required: No
Shift: Day
Clearance Required: Active Top Secret/SCI with the ability to successfully complete a polygraph examination

Position Overview

We are seeking an experienced Senior Software Engineer to support the design, development, deployment, and maintenance of mission-critical enterprise applications. This position is ideal for a hands-on developer who enjoys solving complex technical problems, building reliable software, and collaborating within an Agile engineering environment.
The Senior Software Engineer will work closely with product owners, architects, Scrum Masters, DevSecOps teams, and fellow developers to deliver secure, scalable, and maintainable software solutions.

Primary Responsibilities

• Design, develop, test, deploy, and maintain enterprise software applications using modern development practices
• Develop clean, maintainable, and well-documented code that follows secure coding standards and engineering best practices
• Design and implement RESTful APIs, microservices, and distributed application solutions
• Participate in Agile ceremonies, including sprint planning, backlog refinement, daily stand-ups, sprint reviews, and retrospectives
• Collaborate with product owners, architects, DevSecOps engineers, and development teams to deliver high-quality software
• Develop automated unit, integration, and end-to-end tests to support application quality and reliability
• Perform code reviews and provide technical guidance to junior developers
• Troubleshoot complex application issues and perform root cause analysis
• Collaborate with DevSecOps teams to support CI/CD pipelines and automated deployments
• Optimize application performance, scalability, reliability, and security
• Participate in architecture discussions, modernization initiatives, and technical roadmap planning
• Support production deployments and resolve issues within mission-critical environments

Required Qualifications

• Active Top Secret/SCI clearance
• Ability to successfully complete a polygraph examination
• Bachelor’s degree in Computer Science, Software Engineering, or a related field with 8 to 12 years of relevant experience, or a master’s degree with 6 to 10 years of relevant experience
• Eight or more years of professional software development experience
• Strong hands-on proficiency in at least one object-oriented programming language, such as Java, C#, Python, or C++
• Experience developing web-based applications or enterprise software solutions
• Experience designing, developing, and consuming RESTful APIs
• Experience working with relational databases, NoSQL databases, or both
• Strong understanding of object-oriented design principles and software design patterns
• Experience using Git or another distributed version control system
• Experience working within Agile Scrum or SAFe development environments
• Strong analytical, debugging, and problem-solving skills
• Strong written and verbal communication skills

Preferred Qualifications

• Experience developing cloud-native applications using AWS, Azure, or another cloud platform
• Experience with Docker, Kubernetes, or other container technologies
• Experience designing or developing microservices architectures
• Familiarity with DevSecOps practices and CI/CD tools such as Jenkins, GitLab CI, or Azure DevOps
• Experience with Infrastructure as Code tools such as Terraform or Ansible
• Experience with messaging technologies such as Kafka or RabbitMQ
• Experience with React, Angular, Vue.js, or another modern front-end framework
• Familiarity with Elasticsearch, Redis, or similar enterprise technologies
• Experience following secure software development lifecycle practices
• Security+ or another applicable DoD 8570/8140 aligned certification

Work Environment

• This is a full-time, onsite position based in Gaithersburg, Maryland. Candidates must be able to work onsite during normal daytime business hours.

System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.

System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.